1. Field of the Invention
The present invention relates to a heat generating element which generates heat in the treatment of a living body tissue by heating, a medical therapeutic instrument implementing the heat generating element, and a treatment apparatus.
2. Description of the Related Art
Various medical accessories have been previously proposed. The medical accessories are inserted into body cavities to heat living-body tissues and, for example, coagulate the living-body tissues.
For example, Japanese Patent No. 3523839 discloses a surgical instrument serving as a medical therapeutic instrument having a pair of jaws which are opened and closed through a pivotal portion disposed at the proximal end portions.
In the surgical instrument disclosed in Japanese Patent No. 3523839, a heat generating plate is disposed on the distal-end side in the inside of one jaw of a pair of jaws in the surgical instrument, and the heat generating plate is in the shape of a taper having a width decreasing with increasing proximity to a lower end edge.
A portion of the heat generating plate exposed at the one of the jaws constitutes a treatment surface in the treatment of a living-body tissue by heating, coagulating, cutting, and the like. Furthermore, thin film resistance heating elements are disposed on the perimeter surface of the exposed portion of the heat generating plate, that is, on the treatment surface. The thin film resistance heating elements are electrically connected to a lead wire on the proximal-end side of the one of the jaws. The thin film resistance heating elements are formed by superimposing an insulating layer, a resistor serving as a heat generating portion, a protective layer, and a Teflon coating layer on the heat generating plate in that order to constitute a four-layer structure.
The thus configured surgical instrument disclosed in Japanese Patent No. 3523839 is used for heating a living-body tissue by taking advantage of heat generation of the resistor of the thin film resistance heating elements disposed on the heat generating plate based on the electric power supplied from a power device, so as to, for example, coagulate the living-body tissue.
Japanese Unexamined Patent Application Publication No. 2003-70801 discloses a surgical instrument including a pair of jaws which are optionally opened and closed and which serve as a medical therapeutic instrument used for heating a living-body tissue to, for example, coagulate the living-body tissue.
In the surgical instrument disclosed in Japanese Unexamined Patent Application Publication No. 2003-70801, a heat generating element is mounted on the side-surface side in the inside of one of the jaws in the surgical instrument, and heat generating patterns, e.g., thin film resistance heating elements divided into two parts, for example, a front portion and a rear portion, are disposed on the side surface in the vicinity of an edge portion of the heat generating element.
The thus configured surgical instrument disclosed in Japanese Unexamined Patent Application Publication No. 2003-70801 is used for heating a living-body tissue by taking advantage of heat generation of the heat generating patterns disposed on the heat generating element based on the electric power supplied from a power device, so as to coagulate the living-body tissue.
In addition, a heating member disclosed in Japanese Unexamined Patent Application Publication No. 9-232102 is formed by disposing a resistance layer on a metal substrate, and can be used not only for a medical therapeutic instrument, but also for various purposes.
The heating member is composed of a substrate made of anodized aluminum, aluminum, stainless steel, enamel-coated steel, copper, or the like, an electrically insulating layer disposed on the substrate and made of a silicone resin containing a thermally conductive filler, an electrical resistance layer disposed on the electrically insulating layer and made of a silicone resin containing an electrically conductive filler, an electrically conductive region disposed on a part of the electrical resistance layer, and an insulating protective coating layer disposed on the electrical resistance layer.
The thus configured heating member disclosed in Japanese Unexamined Patent Application Publication No. 9-232102 can improve the resistance against high temperatures and high power densities.